Plug-ins for Mozilla 1.4

I am using Mozilla 1.4 web browser, and I have picked several plug-ins for it. My problem is that I need a midi plug-in. There are all sorts of them online, but after a while it got more confusing. I downloaded a couple, and the web page with the music I wanted still said at the bottom I needed a midi plug-in for Mozilla.
Now I am confused about how to get propler midi plug-in. Can you help? I did find one site which said if I downloaded Microsoft media player 9.0 this would solve my problem, but before I could investigate I lost the page when my netwaiting kick in. Will this work?
Does anyone have a difinitive list of plug-ins that anyone running Mozilla should have so things will run smoothly. I would appreciate any help you can give me.
Thanks
Wilbur Huck